﻿#include <iostream>
#include <vector>
#include <queue>
using namespace std;

class Solution
{
    int m, n;
    int dx[4] = { 0,0,1,-1 };
    int dy[4] = { 1,-1,0,0 };
public:
    // 542. 01 矩阵
    vector<vector<int>> updateMatrix(vector<vector<int>>& mat)
    {
        m = mat.size(), n = mat[0].size();
        vector<vector<int>> dist(m, vector<int>(n, -1));

        queue<pair<int, int>> q;
        for (int i = 0; i < m; i++)
            for (int j = 0; j < n; j++)
                if (mat[i][j] == 0)
                {
                    q.push({ i,j });
                    dist[i][j] = 0;
                }

        while (q.size())
        {
            pair<int, int> p = q.front();
            q.pop();
            int a = p.first, b = p.second;

            for (int k = 0; k < 4; k++)
            {
                int x = a + dx[k], y = b + dy[k];
                if (x >= 0 && x < m && y >= 0 && y < n && dist[x][y] == -1)
                {
                    dist[x][y] = dist[a][b] + 1;
                    q.push({ x,y });
                }
            }
        }
        return dist;
    }
};

int main()
{
    vector<vector<int>> v{ {0,0,0}, {0,1,0}, {1,1,1} };
    for (int i = 0; i < v.size(); i++)
    {
        for (int j = 0; j < v[0].size(); j++)
            cout << v[i][j] << " ";
        cout << endl;
    }
    v = Solution().updateMatrix(v);
    cout << endl;
    for (int i = 0; i < v.size(); i++)
    {
        for (int j = 0; j < v[0].size(); j++)
            cout << v[i][j] << " ";
        cout << endl;
    }

    return 0;
}